1. Field of Invention
The embodiment of the present invention relates generally to a processor and, more particularly, to a digital signal processor used in a motor control system.
2. Description of Related Art
A motor is the main power source in the electromechanics system and is extensively used in all sorts of the system. The advantage of the conventional carbon brush motor is that it is easy to control. The rotation speed of the motor can be changed by regulating the voltage provided to the armature. However, the armature of the carbon brush motor is located at the rotor, and a collecting ring is needed to touch the carbon brush for transducing current from the carbon brush to the collecting ring. As such, there will be spark generated between the collecting ring and the carbon brush simply due to the friction therebetween so that the carbon brush motor is not suitable for some conditions.
The permanent magnet synchronous motor (PMSM) is introduced to solve the shortcomings of the carbon brush motor. The rotor of the PMSM is a permanent magnet, and the field coil is wound around the stator. The permanent magnet rotor is rotated by the excitation of the coil on the stator sequentially. The voltage of the coil of the stator needs to be changed six times each cycle of the rotor, and the above principle is called six step commutation. Comparing with the carbon motor, the PMSM is quieter and has a higher efficiency and higher reliability, and so on.
The PMSM is controlled by a technology of 120 degrees square wave sensorless control. The technology of sensorless control is implemented by feeding back the three-phase back electromotive force signal to a digital signal processor, and the digital signal processor can control a motor based on the position detection signal corresponding to the three-phase back electromotive force signal.
However, the technology of sensorless control adopting feeding back three-phase back electromotive force signal results in unsymmetrical square wave current and increase of the torque ripple caused by unbalanced motor magnetic field distribution, and the drive efficiency is reduced by the above mentioned problems. Accordingly, there exists an urgent need in the related art to provide a solution to address these disadvantages.